Preparation of novel esters of betahydroxy carboxylic acids by the reaction of beta-lactiones with chlorophenols



Patented Dec. 26, 1950 UNITED; STATES PATENT OFFICE PREPARATION OF NOVEL ESTERS OF BETA- HYDROXY CARBOXYLIC ACIDS BY THE REACTION OF BETA-LACTONES WITH CHLOROPHENOLS Warren L. Beears, Cleveland, Ohio, assignor to The B. F.Godrich Company, New York, N.'Y.'; a corporation of New York No Drawing; Application April 18,1949,"

SeriaPNo. 88,236

li fllaimsd (01. 260-479) 1, This "invention relates/to the preparation of novel esters 'of' beta-'hydroxy 'carboxylicacids;

particularly chlorophenyl' hydracrylates; and pertains more specifically to the preparation of such compounds by the reaction of a chlorophenol and a beta-lactone.

It'isdisclosed in U. S. Patent"2,356,459, to Frederick E. Kiing" thatbeta-lactones, that is, lactones or inner estersof*beta hydroxy carboxylic acids may be obtained in good yields by thereaction'of a ketenewithan' aldehyde or ketone. In this manner beta-'propiolactone (also called hydracrylic acid lactone) which has the structure CHz -CHzG -=O is economically obtained from ketene and form aldehyde; Itis'iurther disclosed in acopezidingapzivlication; Serial No. 620,659; filed October '5, 1945,

now Patent No. 2,449,991, that a beta-aroxy carboxylic acid is obta'inedwhen a beta-lactone isllreactedwith a phenol in ithe absen'ce ofadded materials, or in the presence ofian inert organic diluent," or in the presence of an aqueous solution' of-a base'so'as to forma salt of the phenolp Also, it is disclosed in a copending application,"

Serial No. 19,896, filed April 8,:1948, that phenols, cresols and the like react with beta-lactones to form aryl esters": of betaehydroxyi carboxylic acids.

I have "now discovered that when a beta-lactone reacted with a chlorophenol inthe presence of a catalyticamount of?a strongmineral on inorganic acid; reaction occurs atuthe' betacarbonatompfithe beta-lactone to fornra chloro phenyl ester of beta-hydroxy carboxylic acidgr and that this reaction provides a convenient and economical method for preparing numerous useful organic compounds which have not heretoforewbeen prepared.

'Thenovelcompoundsof this invention possess the general formula;

wherein Ar is a chlorophenyl radicalwhichmay contain from 1 to 5 chlorine atoms, each R'is hydrogen or'an'alkyljarylor cycloalkyl radical containin'g fro'ml tofi barbonatomsgand his 0 ce l The re'action to'form the compound? of Strong mineral whereins-Ar and' -R-haveathemeaningeset forth hereinabove-e The compounds of" the above general formula wherein-n is 1, are: prepared by a secondary re action involvingthe\self-alcoholysis-ofthe ester:

first formedby the reaction of the chlorophenolwith the beta-lactone. This secondary reaction, which occurs simultaneously with the primary, reaction,- may be represented as followsz" wherein-Ar and. R are thesame as above. a

In carrying (out the reaction, a preferred procedure involves first adding the strong mineral acid catalyst, such as sulfuric acid, hydrochloricacid, phosphoric acid and the like (preferably in catalytic amounts of approximately 1%-by-: weightbased on the weight of the beta-lactone, although amounts as small "as .2 %Ior smaller-and as high as4% or even higher may be used ac l--- vantageousl-y) to the chlorophenol, and thenf adding the beta la'ctone to the chlorophenol-acid mixture with agitation. However, other procedures such as addition of the acid catalyst to a mixture of therchlorophenolandQthe lactone may also be used. The reaction may also be conducted in an inert solvent or diluent such-as hexane. benzene, carbon tetrachlbride or'the'like oreven tracted with an organic solvent such as ether, benzene, and the like and the extract distilled, although, if desired, the residue itself may be distilled at reduced pressures to obtain the products. Compounds resulting from the primary and secondary reactions described above are conveniently separated from one another during the distillation.

By controlling the reaction time the proportionate amounts of the products obtained from the primary and secondary reactions can be conveniently controlled. For example, when reacting beta-propiolactone with a chlorophenol, highest amounts of chlorophenyl hydracrylate are obtained when the time of reaction is relatively short since the secondary reaction of self-alcoholysis is substantially slower than that of the primary reaction to form the chlorophenyl hydracrylate. When the reaction time is increased substantially higher yields of the secondary reaction product, that is, a beta-(carbochlorophenoxy) alkyl hydracrylate, are obtained. Thus, by selecting the proper reaction time, the desired amount of either reaction product can be obtained.

The quantities of the chlorophenoland the beta-lactone used in the reaction are not critical and may be varied widely. The reactants may be brought together in equimolecular proportions (the quantities theoreticaly required for the reaction), although it is desirable that an excess of the chloro'chenol be utilized. Thus, a chlorophenol-beta-lactone ratio of from 3:1' to 6:1 is preferred although the ratio may be as low as 1:1 or as high as 821 or even higher.

7 Other conditions for the reaction such as temperature and pressure are also not critical. Highest yields of the desired products are generally obtained when temperatures of from 30 C. to

70 C. and atmospheric pressure arewutilizedr However, temperatures as low as C. or lower or as high as 100 C. or even higher are also operative.

Any desired chlorophenol may be reacted with beta-lactones. Included in this class of phenols are ortho-chlorophenol. para-chlorophenol, 2,3- dichlorophenol, 2,4-dichlorophenol, 2,5-dichlorophenol, 2,6-dichlorophenol, 3,4-dichlorophenol, 3,5-dichlorophenol, 2,3,5-trichlorophenol, 2,4,6- trichlorophenol, pentachlorophenol and the like.

Beta-propiolactone, the simplest possible betalac tone, is the preferred beta-lactone for use in this invention b cause of the ease with which it reacts with chlorophenols to produce chlorophenyl hydracrylates and because of its low cost. However, other beta-lactones of the general formula,

R\ /R R R o o--o=0 L' Q wherein each R is a member of the class consisting of hydrogen and alkyl, aryl and cycloalkyl radicals, containing fewer than '7 carbon atoms may be used. Included among the beta-lactones of this general class are saturated aliphatic betalactones such as beta-butyrolactone, which gives chlorophenyl esters of beta-hydroxy butyric acid; beta-isobutyrolactone, which gives chlorophenyl esters of beta-hydroxy isobutyric acid; betavalerolactone, which gives chlorophenyl esters of betay-hydroxy valeric acid; beta-isova-lerolactone, which gives chlorophenyl esters of betahydroxy isovaleric acid; beta-n-caprolactone, which gives chlorophenyl esters of beta-hydroxy caproic acid; alpha-ethyl-beta-propiolactonc, which gives chlorophenyl esters of alphaethyl beta-hydroxy propionic acid; alphai.sopropylbetapropiolactone, which gives chlorophenyl esters of alpha-isopropyl beta-hydroxy propionic acid; alpha butyl beta propiolactone, which gives chlorophenyl esters of a1pha-mutyl-betahydroxy propionic acid; alpha-methyl-betabutyrolactone, which gives chlorophenyl esters of alpha-methyl-beta-hydroxy butyric acid; alphaethyl-beta-butyrolactone, which gives chlorophenyl esters of alpha-ethyl-beta-hydroxy butyric acid, and the like.

Beta-lactones containing cycloalkyl and aryl substituents .such. as beta-cycloheXyl-beta-propiolactone, beta-phenyl-beta-propiolactone, alpha-phenyl-beta-propiolactone and the like may also be used to produce chloro-phenyl esters of the corresponding beta-hydroxy carboxylic acids.

In order further to illustrate the invention the following specific examples are set forthbut it is to be understood that the invention is not limited thereto. All parts are by weight.

Example I .385 parts (3 moles) of freshly distilledparachlorophenol and 0.5 part of concentrated sulfuric acid are placed in a glass reaction vessel equipped with a stirrer, and temperature measuring means. This mixture is heated to about 50 C. and '72 parts (1 mole) of beta-propiolactone are added overa twelve minute period, the temperature of the reaction mixture being main-v tained at about 50 C. by external cooling means. The reaction mixture is stirred for ten minutes and the catalyst neutralized with sodium methoxide. The excess para-chlorophenol is removed by vacuum distillation'and the residue is poured into an ether solution. The ethersolution is washed with a saturated solution of sodium acid carbonate and-with water; Upon distillation of the ether solution 70 parts'of para-chlorophenylhydracrylate are obtained. (B. P. 99 C/lmm.; ND 1.5332; (120 1.2860), analysis: C, 53.54%; H, 4.63%.

A second fraction, 70 parts, is identified as beta-(carbo--chlorophenoxylethyl hydracrylate. g

Example I! Example I is re eated except that ortho-chlorophenol is substituted for the para-isomer. 38 parts of ortbo-chlorophenylhydracrylate (B. F. -82 C./0;03 mm; Nn 1.5283; dzo 1.2620, analysis: C, 55.37%; H, 4.91%) are obtained.

81 parts of beta- (carbo-Z-chlorophenoxy) .ethyl hydracrylate are also obtained as a second fraction.

' Example III I Example I is repeated substituting beta-bu tyrolactone for beta-propiolactone.- Upon dis- Moreover, when other chlorophenols are reacted with beta-lactones in thepresence ofa strong mineral acid catalyst, chlorophenylhywarrants:

"phenol is reacted with alpha butyl-"beta propiolactone in the presence of concentrated *sulfuric acid, the 2,4,6-trichlorophenyl ester of alpha-..

butyl-beta-hydroxy propionicacid and the product resulting from self-alcoholysis of this ester are obtained, and when penta-chlorophenol is reacted with beta-n-caprolactone in the presence of concentrated sulfuric acid, the penta-chloro-i phenyl ester of beta-hydroxy caproic acid and the product resulting from self-alcoholysis of this ester are obtained."'It is tobeunderstood that any of the generic class of chlorophenols will react with any beta-lactone of the general formula wherein each R is a member of the class consisting of hydrogen and alkyl, aryl and cycloalkyl radicals containing fewer than 7 carbon atoms, in accordance with this invention.

As has been indicated hereinabove, the chlorophenyl hydracrylates, the beta-(carbo-chlorophenyl) alkyl hydracrylates and the other chlorophenyl esters of beta-hydroxy carboxylic acids, are all very valuable chemical compounds. For example, they are useful as solvents and plasticizers for resinous and rubbery materials such as cellulose derivatives. vinyl resins, synthetic rubber and the like. The chlorophenyl hydracrylates are especially useful in that they may be heated in the presence of a dehydrating agent, whereupon a molecule of water is removed to form the corresponding chlorophenyl acrylates which are useful polymerizable materials. In addition, the new compounds of this invention are useful as insecticides, fungicides and herbicides and as chemical intermediates and for many other purposes.

Numerous modifications and variations of the invention will be obvious to those skilled in the art and are included within the spirit and scope of the appended claims.

I claim:

1. The method which comprises reacting a chlorophenol with a beta-lactone of the formula wherein each R is a member of the class consisting of hydrogen and alkyl radicals of fewer than '7 carbon atoms, in the presence of a strong mineral acid catalyst and recovering a compound of the formula t it wherein Ar is a chlorophenyl radical, n is a numeral, including zero, less than two and each R has the same meaning as above.

2. The method which comprises reacting a chlorophenol with beta-propiolactone in the presence ofastrong mineral acid "catalystandfrecov- *ering a compound or theform'ula Lt it wherein Ar is a-chlorophenyl radical and n is a numeral, including zero, less than two.

3. The method which comprises reacting a chlorophenol with beta-propiolactone in the presence of a strong mineral acid catalyst and recovering a compound of the formula wherein Ar is a chlorophenyl radical.

4. The method which comprises reacting a chlorophenol with beta-propiolactone in the presence of a strong mineral acid catalyst, and recovering a compound of the formula wherein Ar is a chlorophenyl radical.

5. The method which comprises reacting parachlorophenol and beta-propriolactone in the presence of a strong mineral acid catalyst and recovering para-chlorophenyl hydracrylate.

6. The method which comprises reacting para-chlorophenol and beta-propiolactone in presence of a strong mineral acid catalyst and recovering beta-(carbo-e-phenoxy) ethyl hydracrylate.

7. The method which comprises reacting orthochlorophenol with beta-propiolactone in the presence of a strong mineral acid catalyst and recovering ortho-chlorophenyl hydracrylate.

8. The method which comprises reacting orthochlorophenol with beta-propiolactone at a temperature of from 40 C. to 60 C. and in the presence of a sulfuric acid catalyst, and distilling the reaction product to recover orthochlorophenyl hydracrylate and beta-(carbo-Z- chlorophenoxy) ethyl hydracrylate.

9. A new chemical compound of the formula RR R i ll

wherein Ar is a chlorophenyl radical, each R is a member of the class consisting of hydrogen and alkyl radicals of fewer than '7 carbon atoms, and n is a numeral, including zero, less than two.

10. A new chemical compound of the formula wherein Ar is a chlorophenyl radical, and each R is a member of the class consisting of hydrogen and alkyl radicals of fewer than 7 carbon atoms.

11. A new chemical compound of the formula R\ /R R /R R R R R Ar-O("]--CC-0J C C ,-0H

wherein Ar is a. cholorophenyl radical, and each O-U-CHQCEl-=O-C-CHP-C P- R is a member of the class consisting of hydrcg gen and alkyl radicals of fewer than 7 carbon atoms. 5

12. As a new chemical compound para-chlorophenyl hydracrylate of the formula 5 1 OCCHr--CHa-OH 14. As a. new chemical compound ortho-chlorophenyl hydracrylate of the formula 10 o-c-cm-cm-on 13. As a new chemical compound beta-(carbo- WARREN BEEARS.

-chlorophenoxy) ethyl hydracrylate of the formula No references cited. 

1. THE METHOD WHICH COMPRISES REACTING A CHLOROPHENOL WITH A BETA-LACTONE OF THE FORMULA 